A method for partial detachment or removal of a conductive layer from a, for example, flexible or polymer circuit substrate, in particular also a three-dimensional circuit substrate, or from a conventional printed circuit board is known from DE 10 2004 006 414 B4, for instance, and is used in practice in particular when it is not possible or desirable to remove the required area chemically, which is the case in the field of prototype fabrication, for example.
Using laser radiation to remove a conductive layer is hence already fundamentally known. Provided the material properties of the substrate have far higher limiting values compared with the conductive layer, in particular with regard to the laser ablation limiting values required in a particular case or even the melting points, the laser parameters can be set such that only the conductive layer is removed by the laser beam, whereas the substrate is not damaged or affected. For this purpose, the zone to be removed is heated by a laser beam. The area to be removed is composed of individual zones, which may be in the shape of strips, with the bounding recesses running substantially along parallel straight lines.
U.S. Pat. No. 3,214,315 relates to a method in which a stamp is used to separate the conductor track mechanically from the area to be detached, the stamp being warmed in order to achieve weak adhesion of the area to the substrate. Once the area has been removed, further heat input is used to cure the substrate and hence to permanently bond the conductor tracks to the substrate.
A method for laser removal of conductive layers by reducing the adhesion between conductive layer and substrate is known from EP 0 834 191 B1. Similar methods are also described in US 2003/0047280 A1 and JP 2003-47841 A.
US 2001/006766 A1 discloses a method in which electromagnetic radiation is used through the surface of the area to weaken the bond between the area and the substrate in order subsequently to detach the area in these zones. The advantage lies in the reduced amount of energy input to achieve this, which is low compared with the ablation energy of the layer.
DE 694 11 337 T2 teaches a method for producing a conductive circuit on a resin moulding, in which an applied metal film is exposed to laser radiation along the boundaries of a portion that is to be formed in the conductive layer, in order to remove the exposed metal film. The portion of the metal film that is not needed for the circuit is removed by chemical etching.
In addition, a method for removing a conductive layer from a dielectric substrate is known from US 2002/0106522 A1, in which initially a cut is made using a laser beam along the boundary line of that region of the conductive layer that is to be removed, and then the conductive layer is peeled off.
WO 90/09730 A1 teaches a method for producing an electrode pattern from a layer made of electrically conductive material on an insulating substrate by means of a laser beam, said electrodes being in the shape of strips. Removal is performed by means of compressed air or suction.